My Home Ideas

Special Offers

Be the first to know about This Old House contests, sweepstakes, and events and receive special offers and promotions from your favorite home improvement brands. We'll even send you regular reminders to enter our sweepstakes.

If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Sealing ductwork - mastic or foil tape???

I am working in my unfinished basement to seal our duct work to prevent the leakage of air from the gaps. There are a few larger gaps and many smaller. In talking to one local HVAC company, they use mastic. Another uses more tape than mastic. Code locally seems to use either foil tape OR mastic.

I have tried searching multiple places and cannot find a solid reason to use one over another. I am leaning towards foil tape since I have more experience with it. Does anyone have any advice on this?

Re: Sealing ductwork - mastic or foil tape???

With little experience with either, my gut instinct is that mastic would last longer. Though the foil tape designed for ducts is superior to other tapes, I would be afraid of the adhesive drying out eventually causing the tape to peel off. The mastic seems like it would maintain its bond with the ductwork.

Of course, I could be wrong.

The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.